A solution of barium hydroxide, #Ba(OH)_2# contains 4.285 grams of barium hydroxide in 100 mL of solution. What is the molarity of the solution?

Question

Wyatt Atkins · Accepted Answer

2.5 M

We know the molar mass of barium hydroxide is 171.34 (you can google this or just add the mass of each atom in the molecule). Knowing that #molarity = (mols) / (liters)# we need to turn that 4.285 g Ba(OH)2 into mols. To do this, divide 4.285 g by the molar mass of 171.34 g, which yields 0.2500 mol of Ba(OH)2. Plugging this all back into the equation for molarity we get #molarity = (0.2500 mol)/(0.100 L) # giving us a molarity of 2.5 M

Jose Ayala · Answer

undefined To find the molarity of the solution, divide the number of moles of solute (barium hydroxide) by the volume of the solution in liters.

1. Calculate the number of moles of barium hydroxide:
   $ \text{moles} = \frac{\text{mass}}{\text{molar mass}} $
   The molar mass of Ba(OH)_2 is 171.34 g/mol.

2. Convert the volume of the solution from milliliters to liters (100 mL = 0.1 L).

3. Calculate the molarity:
   $ \text{Molarity} = \frac{\text{moles}}{\text{volume (in liters)}} $